Mr. Noel Carroll:

The first point to make is that pyrite is a ubiquitous mineral present in a lot of rock. To put it in very simple terms, it depends on the type of pyrite it is but more than anything else it depends on the type of rock that it is present in. In Dublin and its surrounding area the pyrite was in good quality limestone and did not create any problem. Where it is present in mud stone it creates the problems because the mud stone is weak and the pyrite begins to expand in it. It is very interesting to see. One sees stone all around the city of Dublin; all the historic buildings, including this one, are all built in stone that has been there for hundreds of years and nothing has happened to it. There is probably pyrite in it. With mud stone containing pyrite, it is hardly in the ground before it starts to react. One can see the chemical reaction and within a very short time it breaks in one's hands when picked up. As it is such a ubiquitous material the means of determining whether a stone is at risk or not is through the testing standard, which works well. It breaks down the individual chemical constituents and the various physical properties of the stone. It is not very difficult to do.

Now, one might say one quarry is okay and another is not but it is rarely that simple because there are different seams within different quarries. The same quarry can have a harmful seam and that is why the management at the quarry, the process - as Ms Neary mentioned earlier- and the production control systems are so important. Another element is that products are produced for different purposes. One might take a load of the stone and decide to lay a temporary pathway into a field or something like that, and it will be suitable for this purpose, but one would not put it under the floor of a house. That is why it is important to specify the stone that one has and to get evidence to support this, to have the paper trail on that. If I were a builder and I was building houses regularly, given the history of these things in the past, I would do some testing on the site to keep them straight. A code of practice is being prepared and is at an advanced stage. I believe it is out for public consultation. The purpose of the code is to advise people on the procurement of stone and how they should go about it. That should cover all the trials. I should also add that in the remediation process the PRB is carrying out, it is being ensured and certified that the stone that is going back under the houses meets the standards and that it is appropriate for its purpose and will not cause further problems.